The ONLY way to totally protect your RV is to get a Progressive Industries EMS system, either portable or hard wired. In it's first season in 2016, ours saved our TT from serous OVER voltage several times a day for 5 days at a NY State Park ( Cayuga Lake State Park). In speaking to a park ranger, he acknowledged they were fully aware that there were over voltage problems at the Park for "several " years and had not received funding to fix them. He said very few campers have an advanced EMS like mine so are unaware of the cumulative long term damage and shortening of life they are causing to their major electronics and systems in their RV's. In the very next NY State Park in Ithaca, we had our system shut us down several times for UNDER voltage! GET ONE OF THESE UNITS NOW!